README.md

prebaked-geojson-map

This package makes it very easy to add GeoJSON data to a to a preconfigured Leaflet map.

Installation

npm install --save-dev prebaked-geojson-map

Usage

This module exports a UMD object named PrebakedGeoJSONMap; you can see the exported members in src/index.ts.

Here are the basic steps to use this module in a webpage:

1. Load this module's index.css and index.js into your page.
2. var map = window.PrebakedGeoJSONMap.add();. .add takes the same options as Leaflet's L.map. It includes some default options (see src/map.ts) and automatically adds some base layers (see src/layers.ts).
3. Add data to the map with window.PrebakedGeoJSONMap.renderPaths(data, map); and window.PrebakedGeoJSONMap.renderPoints(data, map);. data must be valid GeoJSON data, either as a JavaScript object literal or via JSON.parse.

You can see these steps demonstrated by example/index.html. The instant-map project is slightly more complex; the user drags a GeoJSON file into the browser window and the GeoJSON data is projected on the map.

The Map instance returned by .add has some custom event listeners that work around limitations in Leaflet’s API:

• "addBaseLayer" allows you to add a new base Layer to the existing layers control. Leaflet’s API only allows you to add new layers by calling L.control.layers, which will always add a new control. Use it like map.fire("addBaseLayer", { baseLayer: layer, key: 'foo' });.
• "addOverlayLayer" allows you to add a new Layer or LayerGroup overlay to the existing layers control. Use it like map.fire("addOverlayLayer", { overlayLayer: layer, key: 'foo' });.
• "resetOverlayLayers" allows you to remove all the overlay layers from the layers control. Use it like map.fire("resetOverlayLayers"). Note that this will not remove Markers added by .renderPoints: to remove those, run map.eachLayer(layer => { if (!layer._url) map.removeLayer(layer) });.